Role Of Cancer As A Genetic Disease

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Case Study: BIOT 635 Prahelika Reddy ROLE OF ONCOGENES IN CANCER RESEARCH 1. Introduction The idea that development of cancer as a genetic disease was first postulated by Cavenee et al and developed by Fearon and Vogelstein. According to COSMIC (Catalogue of Somatic Mutations in Cancer) database, the current list of known somatic genetic mutations leading to cancer is 522. Genes which undergo mutations leading to cancer can be classified into two groups - Proto-Oncogenes and Tumor Suppressor genes. Proto-Oncogenes are the genes that are responsible for cell proliferation i.e. they code for the proteins that are responsible for growth of cell. Tumor Suppressor genes have an opposite effect and code for proteins that regulate cell cycle and…show more content…
The first oncogene targeted anti-cancerous agents are Gleevec and Herceptin. Gleevec is a small molecule designed to target tyrosine kinase (enzymes that activate many proteins by signal transduction cascades) encoded by bcr/abl oncogene. Herceptin is a monoclonal antibody which interferes with the receptors responsible for activation of proteins which signal cell proliferation. It was earlier thought that up to seven independent genetic hits are necessary for the development and progression of a malignant cancer[Fearon ER and Vogelstein B, 1990], but recent studies suggest that abnormal expression of only three genes might be sufficient for normal cells to convert to cancer cells [Hahn WC et al 1999]. In one such case (H-ras, hTERT, SV40LT) the cancer causing genes were all dominant and transformed proto oncogenes. Also, in this case inactivation of a single oncogene (e.g., mutant ras) can result in tumor regression which implies that in some cases (e.g., mutant ras) continuous expression of oncoproteins is functionally important, non-redundant and indispensable for sustained tumor growth despite a great number of genetic and epigenetic complexities associated with tumor formation. This phenomena is called “Oncogene Addiction” and it provides a rationale for targeted therapy. Thus, Oncogenes have attracted a great deal of interest as molecular targets for cancer therapy in recent years.
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